Patent GB-190520819-A (GB)
Title: Improvements in and relating to the Application of Rotary Electric Motors to Work Certain To-and-fro Movements and in a Gearing Device and a Pump and a Fluid Motor with which the same can be Effected
Inventor: HARDY GEORGE HUDLESTON HURLSTO
Filed: 1905-10-14
Granted: 1907-01-10
Abstract: 20,819. Hardy, G. H. H. Oct. 14. Crossing-gates; points. - Railway points and, according to the Provisional Specification, crossing- gates are operated by rapidly - rotating - electric motors by causing the motor to drive an hydraulic or pneumatic pump through reduction gearing, the fluid from the pump being supplied to a reciprocating fluid-pressure motor, connected to the part to be moved. One form of gearing consists of a concave worm W, Figs. I and IV, mounted upon the motor shaft D and engaging with a wheel R which is provided with cylindrical roller pinions and carries a pair of eccentrics H, connected by reciprocating arms C and a link L to the pistonrod of the-pump. Cranks may be substituted for eccentrics, and a fly-wheel W<1> may be mounted upon the motor shaft. The pump and fluid motor, shown in Figs. II and III, respectively, each have two pistons P on the one piston-rod, working in two cylinders arranged end to end. The pump is provided with outlet and inlet ports 1, 3 respectively for the left-hand cylinder, and outlet and inlet ports 2, 4 for the right-hand cylinder. The motor is furnished with change-over ports 5, 6, 7, 8. In addition, the motor is provided with chambers A serving as accumulators, into which the fluid is forced before it enters the cylinders, compressing the air or other fluid therein. The chambers may be separate from the motor cylinders, or they may be attached to the pump. Fluid is pumped from one chamber A to the other by means of the pump. In operation, to drive the piston-rod of the motor from right to left, fluid is forced alternately out of the passages 1, 2 of the pump into the inlet 5 of the motor, and is drawn into the pump alternately by passages 3, 4 from the outlet 8 of the motor, the ports 6, 7 of the motor remaining closed. At the commencement of the reverse stroke, the ports 6, 7 are open and the ports 5, 8 closed. The fluid then comes out of the passage 7 back to the ports 3, 4 of the pump, and is forced through the outlets 1, 2 into the inlet 6 of the motor. The passages 1, 2, 3, 4 are furnished with automatic non-return valves. The change-over cock for the ports 5, 6, 7, 8 is worked by a rack 15, attached to a piston-rod 13 working within two cylinders 14 in communication with the accumulator chambers A by means of pipes 9, 11 and 10, 12. The rack 15 is held at the end of each stroke by stops 17, 18. To lengthen its throw, the motor shaft 16 may be connected to the driven member by a lazy-tongs. In some cases, only one-half of the motor is used, the return stroke being made by gravity. A pneumatic pump and motor are shown in Figs. VIII, IX*, and IX**. The outlet passages 1, 2 of the pump are connected alternately to the inlets 5, 6 of the accumulator chambers A. The air inlets 3, 4 of the pump are open, and the pipes 7, 8 of. the accumulator chambers are exhaust ports. The compressed gas is conveyed by pipes m*, m**, to the cylinders of the motor. In a third arrangement, the pump is arranged to transfer liquid from one accumulator chamber to the other, the air which is compressed in these chambers working the motor. Another form of fluid motor, Fig. X, is provided with a double-faced piston and two pairs of inlet and outlet ports 5, 6, 7, 8 in connexion with a changeover cock. The accumulator chambers A form circumferential jackets. In order that the fluid compressed in the accumulator chambers may assist the quick commencement of the return stroke, an ordinary steam-engine slide valve is added to the pump in place of the change-over cock, and a compressed gas such as air or carbon dioxide is employed in the motor cylinders, being admitted through valves 21, 22 of the pneumatic-tyre inflation type, or by inlet valves which admit air only when the pump has lowered the pressure without completing the motor stroke. A lubricating oil duct 20 is added. According to the Provisional Specification, several pairs of pumps may simultaneously work one or more fluid motors. Like constructions of worm gearing are described in Specifications No. 2890, A.D. 1878, No. 305, A.D. 1884, No. 17,129, A.D. 1897, and No. 11,535, A.D. 1899, [Abridgment Class Mechanism &c.] ; combinations of fluid pumps and motors and other matter of interest in Specifications No. 23,902, A.D. 1893, Nos. 7479 and 11,481,A.D. 1896, [Abridgment Class Air and gases, Compressing &c.], Nos. 12,128 and 14,826, A.D. 1897, No. 3849, A.D. 1899, No. 22,406, A.D. 1901,No. 7800, A.D. 1902, [Abridgment Class Mechanism &c.], Nos. 442 and 10,222, A.D. 1903, and No. 12,751, A.D. 1904, [Abridgment Class Electricity, Regulating &c.] ; and examples of the working of railway points and signals in Specifications No. 2163, A.D. 1861, [Abridgment Class Oils &c.], No. 2174, A.D. 1861, Nos. 4976, 20,896, and 22,570, A.D. 1893, [Abridgment Class Railway signals &c.J, and No. 11,005, A.D. 1905,